I have a friend that is going to Yellowstone/Grand Teton and wants to know if what you guys think of the 80-400 as a wildlife lens. Heard rumors that it's pretty slow in focusing, but is there anything else we need to consider?
Wes :
The 80-400mm lens takes a bad rap from a lot of folks, but it's actually a very capable lens. Yes, the focusing is slower than the AFS lens type, but it's reasonably good with a little planning. The zoom focal length range is excellent, and again, with some planning, it allows the photographer to frame a photograph to minimise cropping, or alternately, to "step back" with the zoom so as not to overfill the frame or cut off desired image sections.
Where the 80-400mm lens will not be as beneficial is under low light conditions with rapid movement. It's fine for shooting, say a slowly moving bison or a stationary moose, but it's not going to work as well for quickly flitting birds at sunset. Knowing how an animal will move and anticipating the direction will allow you to maintain a focus lock, or alternately, to pre-focus for where the critter will be.
The nice thing about the 80-400mm lens is that's very much a "handholdable" lens for a lot of shooting, where a lens like the 400mm f/2.8 is clearly not. The VR function further assists in this aspect of the lens. In very low light, you're better off using a tripod (and don't forget to turn the VR off when stationary tripod shooting !).
I hope that this helps.
John P.